Update (12-21-19): An Asian giant hornet was recently discovered just south of the Canadian border in the town of Blaine, Washington. The dead specimen, collected by the Washington State Department of Agriculture (WSDA), was confirmed as Vespa mandarinia. A live specimen, believed to be the same species, was also seen at a nearby hummingbird feeder.
Back in August, three other specimens were found just north of the border in Nanaimo, B.C. There, the nest was eventually found and destroyed, but officials and beekeepers remain vigilant.
The hornets, which can reach nearly two inches in length, can decimate a honey bee hive, sometimes in a matter of hours. They are skilled hunters that prey on many types of insect, but honey bee hives are convenient for the voracious predators.
Like most hunting wasps, their numbers peak in late summer, so they they are commonly seen in July through October. They have distinctive orange-yellow heads with large black eyes, nest in inconspicuous underground cavities, and can deliver a powerful sting.
Curiously, the WSDA advises residents to stay away from the hornets, but requests a photo should you happen to see one.
The following post was written about beekeeping in France with the closely-related Asian hornet, Vespa velutina.
After I wrote about the Asian hornet (Vespa velutina) entering Great Britain, a beekeeper living in southern France wrote to me about his five-year struggle with these aggressive bee eaters.
Michael Judd, originally from England, keeps ten hives at an elevation of 789 meters (2588 feet) under a small wild-flower-covered mountain near the village of St. Vallier. These higher elevation hives have remained free of the hornets. But he also keeps a couple of small hives in his backyard where the hornets thrive. Here in his backyard is where he has been experimenting with control measures.
Sadly, Michael had an inauspicious beginning with hornet control. His local bee association in cooperation with the government started a program to research solutions to the hornets. Michael signed up for an experiment and agreed to follow all the rules. As a result, he lost all four of his garden hives.
Furious with the deal, Michael asked for compensation. Although none came, he was introduced to a local beekeeper with 70 colonies who builds hives and raises queens and nucs. Even better, he is actively developing ways to deal with hornets. Happily, the ensuing friendship outweighed the loss of Michael’s experimental colonies.
Here is Michael’s take on controlling Asian hornets.
I have lived with Asian hornets for about five years. At first, I lost five hives, then I improved the defenses and so did the bees
The first thing to know about the Asiatic hornet is that, unlike its European counterpart, it hovers in front of a bee hive. This makes for the first line of defense for the beekeeper. A badminton racquet makes it really easy to swat them. I am fortunate that I can have bee hives in my garden so my physical presence gives me the ability to visit often during the day and swat them. A more remote location makes this somewhat difficult.
The Asian hornet life cycle
Asian hornets all die off at the end of the summer, in my case around the end of October. A mated queen or queens then go and hide in a tree or in the ground. They emerge in spring (about April) and search for a place to make a temporary nest. This is a small one, possibly the size of a golf ball. She lays a few eggs there, yielding 6 or 8 hornets. They then search for firstly food and secondly a place, usually high up a tree, to make the main nest.
The hornets are said to only want protein at the end of the summer. Before that they feed just like bees and sometimes together on the same plant. I spotted them in April (South of France near Nice) on a plant that was flowering.
Trapping the queens
I put out a trap made out of a plastic water bottle with a bought product that is a special hornet attractive. This is important, as catching the queens at this time reduces the chance of a large colony being formed. At his time of the year I catch and also swat a reasonable number of hornets, sometimes up to 10 a week. Once the main colony has been formed, with a nest that can be several feet round, there seems to be little chance of finding the nest, which is usually high up in a tree.
For a while during the early summer the hornets seem to disappear. But not completely, as from time to time I see one or two around my hives at the other side of my garden. But by the time mid July/August comes along the hornets can be seen flying about the hives.
The hornet hovers outside the hive and awaits a departing or returning bee and catches it in mid air. It takes the bee to a tree where it takes the wings and head off and then the hornet takes the bee to its nest.
The hornet will only go into the hive when the bees are very weak, not flying, and unable to attack in numbers. I have seen the bees on an entrance or inside the muzzle (see below) attack and kill a hornet, so generally the hornets do not seem to like going in the hive. However, I notice that at this time of year, mid to late September, the hornets are desperate for protein and they get more bold.
How the honey bees react
The reaction of the bees is to feel trapped in the hive. There is a siege going on and their flights are down to an unsustainable minimum. Without any action, the colony will simply reduce in strength until it fades away. In my first year, I found 2 or 3 very small (the size of a tennis ball) swarms in the garden. I got the impression they swarmed out of total desperation. At other times the bees ate all their stores and simply died.
I have noted and read on blogs that up to about 3 hornets around a hive allows the bees to more or less fly normally, but any more than that forces the bees to stay in the hive.
First, I put out several traps. Some made of plastic water bottles and some purpose-built wasp traps. I use two different liquids. The first is an “attractive” bought from my bee association. Sometimes I add a little honey-soaked beeswax. The second is a mixture of white wine, apple vinegar, and cassis. Both of these work very well. A lot of people recommend beer, but I find that it does not work. This year I put both mixtures out in 6 traps (3 each). At the height of the rush, I was catching between 10 and 20 a day.
The next thing I do is to reduce the entrance to the hive. This, of course, makes it easier for the bees to defend their entrance. Then I add what the French call a “muzzle.” It is a wire contraption (see photo) with the holes in the wire measuring 13 mm square (0.5 inch). This allows the bees to enter, but the much bigger hornets are very reluctant to enter as the bees attack them inside. This allows the bees a safe area where they can see the hovering hornet, and either go the other way or exit later.
The bees’ line of defense
What I noticed with one of my hives which had Italian bees is that they set up a line of bees on the floor of the muzzle and this acted as a defense and landing and take off strip for arriving and departing bees. They ware also in position in large numbers to attack any hornet silly enough to get too close. It seems to take the bees about 20 minutes to kill a hornet. It is also interesting to note that a guard bee is often seen scouting around the hive after I have swatted hornets. The scout appears to give the “all clear” when she does not see any more hornets.
This year I noticed that the hornets, rather than hovering directly in front of the hive entrance while waiting for a returning bee, would hover underneath the hive. I found it therefore impossible to swat them with my badminton racquet. So I took a piece of old bed sheet and cut it to fit to the base of the hive and tall enough to get to the ground. I put a skirt on the back and front of the hive. This really seemed to annoy the hornets as they attacked the sheet and could not get to the bees. The result, for me, was they had to hover in front to the entrance and I could swat them easily.
I would also note that when I approach the hive with my badminton racquet, the bees would not react. I would calmly swat, say, a couple or more hornets and the rest would disappear. They are very frightened of me, it seems. The other thing I noticed was if, for example, there were three hornets in the area and I swatted all three, it would take over an hour before any hornets returned.
Everything taken together
The object of all the defenses is to make it more difficult for the hornet to be able to sustain an attack. To this end, I have been moderately successful as I have kept hives operating, harvested honey, and got the colony through the winter..
None of these measures on their own make much difference. However all measures together allowed me to keep the hive strong. In early spring I had 4 hives in my garden and I took 3 of them to another location where I keep most of my hives. At this location (16 kilometers away and 780 meters above sea level) for reasons unknown, there are no hornets yet, so I moved 3 away for safety.